US contractors driving to Canada, a cross-border mileage guide

What to take away

When a US contractor's business drive crosses into Canada

A contractor in Buffalo who drives to a client in Fort Erie has made an international trip. So has a consultant from Seattle heading to Vancouver, or a Detroit engineer visiting a Windsor plant. The drive is ordinary business travel, and the miles are ordinary business miles.

The IRS does not care that the road crosses a border between the United States and Canada. Publication 463 sets out what counts as a business mile: driving from one work location to another, from your home office to a client site, or to a temporary work location away from your tax home.

A Canadian client site is a work location. The same publication covers travel expenses away from home, including transportation, lodging and meals.

What changes is everything around the drive. You buy fuel in Canadian dollars. You pay tolls at the Ambassador Bridge or the Peace Arch in Canadian dollars. Your hotel bill arrives in Canadian dollars. Your mileage log has to survive a currency question and a substantiation question at the same time.

Each pattern produces a different mix of deductible miles and deductible travel costs. A day trip is mostly mileage. A multi-day trip is mostly lodging and meals, with local driving on top. The long-haul drive is mileage plus the costs of getting there.

The border itself is not a tax event. It is a records event. Customs and border records, fuel receipts in a second currency and a log written after the fact are the things that get examined. Start with the general travel framework in Publication 463 before you decide how to split the trip.

If you are a sole proprietor, the profit from Canadian clients lands on your Schedule C alongside US work. If you operate through a partnership or an S corporation, the vehicle question may sit with the entity instead.

Form 1099-NEC from a US payer and Schedule K-1 (Form 1065) from a partnership both feed the same return. The mileage treatment does not change because the client sits north of the line.

What the US Canada tax treaty does and does not cover

The US Canada tax treaty allocates taxing rights between the two countries. It tells you when Canada may tax your business profits and when the United States may. It does not create a mileage deduction, and it does not exempt your driving costs from US rules.

Under the treaty, business profits of a US resident are generally taxable only in the United States unless you have a permanent establishment in Canada. A permanent establishment usually means a fixed place of business, such as an office, a workshop or a dependent agent who habitually concludes contracts.

A laptop in a hotel room is not one. A client's conference room you use twice a year is not one.

That distinction matters for a contractor who spends weeks in Canada. If you cross into permanent establishment territory, Canada can tax a share of the profit, and you may need a Canadian filing. Mileage does not decide that question, but the number of days and the nature of your presence do.

For personal services the treaty uses a day count rather than a fixed place. Presence in Canada of more than 183 days in any 12-month period takes the income out of the exemption, and Canada can tax it.

The treaty also has a tie-breaker for dual residents and rules for dependent personal services. Most short consulting trips fall under the business profits article and stay taxable only in the US. Read the treaty text and the IRS international taxpayer guidance before you assume your trip is covered.

What the treaty does not do is let you deduct a Canadian commute, ignore the standard mileage rate, or skip currency conversion. Treaty relief is about which country taxes the income, not about how you compute the expense.

The USMCA is a separate agreement and does not govern tax. It governs trade in goods and services. It touches the mileage question in one narrow way. If you carry tools or equipment to a Canadian job site, trade rules govern what you may bring across, while the deduction for the drive still follows Publication 463.

The USMCA guidance from the Department of Labor covers labor provisions that can apply to service providers, which is a different question from your mileage deduction. Those labor provisions affect who may do the work and on what terms. They do not change the business miles you log or the deduction you claim.

Currency conversion for Canadian fuel, tolls and parking

Every Canadian dollar you spend on the business drive has to become a US dollar figure on your return. The IRS expects a consistent, reasonable method, applied the same way all year.

You have two workable approaches. Convert each transaction at the exchange rate on the transaction date. Or use an average rate for the period, such as a monthly average, if the rate does not swing wildly. The first is more precise and more work. The second is easier and defensible if you cite a published source.

Name the IRS yearly average currency exchange rates, or the daily rate your card network posts, such as Visa or Mastercard.

Do not use one rate for the whole year and call it done. Do not use the rate from the day you filed. Pick a method, write it down, and apply it to fuel, tolls, parking, lodging and meals alike.

The converted total is what enters your records. Keep the original Canadian amount next to it so a reviewer can follow the math.

Credit card statements are useful here because the issuer already converted the charge and often shows both amounts. That gives you a documented rate without extra work. For cash purchases, note the rate you used on the day.

If you use the standard mileage rate, the rate is in US cents per mile and no conversion is needed for the mileage itself. Conversion applies to the tolls, parking and other costs you deduct separately.

Review how the rates are set each year with a sceptical eye at mileage rates, because a rate change shifts the arithmetic on every trip.

Recordkeeping for miles driven on the Canadian side

Recordkeeping is where cross-border claims fail. The IRS wants a contemporaneous record of the business purpose, the mileage, the dates and the destinations. A Canadian trip adds a currency dimension and a border dimension to that list.

A log entry for a Canadian day should carry the date, the start and end odometer readings, the route, the client or site visited, and the business purpose. Add the border crossing point and the province. If the same day includes personal driving in Canada, separate it.

Write the log the same day or the next morning. A log reconstructed in April for a trip in September is weak evidence, and it invites questions about every other entry.

Keep receipts for tolls, parking and fuel, even though the standard mileage rate already covers fuel, maintenance and depreciation for the mileage portion. If you deduct actual expenses instead, fuel receipts become directly deductible and the record matters more.

The choice between the two methods is not permanent for every vehicle, but it is sticky once made. Compare the outcomes before you commit, using worked comparisons such as mileage rates examples to see how a low business use vehicle behaves under each method.

Store the records for at least three years after the return is filed, and longer if you claim a loss or the IRS questions the return. The general standard for what counts as adequate support is set out in the 1099-nec filing requirements for small business. It applies to Canadian trips exactly as it applies to domestic ones.

Reporting cross-border vehicle expenses on Schedule C

Sole proprietors report business income and expenses on Schedule C (Form 1040). Car and truck expenses go on line 9, with the method and the business mileage entered in Part IV of the form. The IRS overview of Schedule C explains what the form captures and how the car expense section is completed.

The mechanics are the same whether the miles were driven in Michigan or Ontario. You report total miles, business miles, commuting miles and the method used. The Canadian portion is not a separate line. It is part of the business mileage total, supported by records that happen to include a border.

Here is a worked example. A Denver consultant drives to a client in Calgary, a round trip of about 1,700 miles, with 60 miles of local driving at the destination.

If you operate through an S corporation and take a shareholder distribution, the vehicle may belong to the corporation and the deduction lands on the corporate return instead. If you receive a Schedule K-1 (Form 1065), your share of partnership income and expenses flows to your personal return, and the vehicle treatment follows the partnership's method.

State returns matter too. California, New York and other states with their own conformity rules generally start from federal figures, but rates and addbacks differ. Check your state Department of Revenue guidance before you assume the federal number carries through.

Where the IRS international taxpayer guidance fits

The IRS maintains a section for taxpayers with cross-border issues. It covers residency, foreign income, foreign accounts and the treaties that allocate taxing rights. The IRS international taxpayer guidance is the starting point when your Canadian work raises a question the domestic instructions do not answer.

That guidance will not tell you how to log a mile. It tells you whether you qualify as a US resident for treaty purposes, how foreign tax credits work if Canada taxes part of your profit, and what reporting you owe on foreign accounts. Those questions sit above the mileage question.

Two mechanics matter here. If Canada taxes part of your profit, you claim the foreign tax credit on Form 1116. Translate the Canadian tax into US dollars at the IRS yearly average exchange rate for that year.

If your days of presence cross the treaty's 183-day count for personal services, Canada can tax that income, and you may owe a Canadian return. The credit is how you avoid paying tax twice on the same profit.

Before any trip, check the practical side as well. The USAGov travel page covers documents, entry requirements and traveler information for crossing between the United States and Canada, which is separate from the tax question but part of the same trip.

Run through the business meals deduction limit for small business before you file, and revisit the method choice each year. If your business use of the vehicle is low, the comparison in actual car expenses vs standard mileage shows why the standard rate often wins on simplicity.

Common questions